For long term cardiopulmonary support equipment such as long-term PCPS or ECMO, centrifugal blood pumps that can be used for two weeks to one month are presently demanded. The centrifugal pump that use magnetically-levitated technology for the bearings that supports an impeller has been partly sold and developed in order to enhance durability of bearings section and to reduce bloodclot formation and haemolysis (e.g., referred to WO 2007/029623 A1; Hoshi et al., Magnetically Suspended Blood Pump with a Radial Magnetic Driver, ASI0 journal, pp. 60-64, (2005)). In order to achieve sufficient stiffness of the magnetic bearing, high performance magnets such as neodymium magnets are used at a disposable impeller section in all of these pumps. Neodymium magnets are also used at disposable centrifugal pump using many mechanical bearings in order to generate magnetic coupling to transmit torque from a motor to an impeller.